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A Cryocondensation Pump For The Diii D Advanced Divertor Program
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Book Synopsis A Cryocondensation Pump for the DIII-D Advanced Divertor Program by :
Download or read book A Cryocondensation Pump for the DIII-D Advanced Divertor Program written by and published by . This book was released on 1992 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A cryocondensation pump was designed for the baffle chamber of General Atomics DIII-D tokamak and will be installed in the fall of 1992. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long and located in the lower outer corner of the vacuum chamber of the machine. It consists of a 1 m2 liquid helium-cooled surface surrounded by a liquid nitrogen-cooled shield to limit the heat load on the helium-cooled surface. The liquid nitrogen-cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. A thermal enhancement coating was applied to the nitrogen shell to lower the maximum temperature of the shell. The coating is non-continuous to keep the toroidal electrical resistance high. The whole pump is supported off the water-cooled vacuum vessel wall. Supports for the pump were designed to accommodate the thermal differences between the 4 K helium surface, the 77 K nitrogen shells, and the 300 K vacuum vessel supporting the pump and to provide a low heat leak structural support. Disruption loading on the pump was analyzed and a finite element structural analysis of the pump was completed. A testing program was completed to evaluate coating techniques to enhance heat transfer and emissivity of the various surfaces. Fabrication tests were performed to determine the best method of attaching the liquid nitrogen flow tubes to their shield surfaces and to determine the best alternative to fabricating the different shells of the pump. A prototype sector of the pump was built to verify fabrication and assembly techniques.
Book Synopsis Installation and Initial Operation of the DIII-D Advanced Divertor Cryocondensation Pump by :
Download or read book Installation and Initial Operation of the DIII-D Advanced Divertor Cryocondensation Pump written by and published by . This book was released on 1993 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phase two of a divertor cryocondensation pump, the Advanced Divertor Program, is now installed in the DIII-D tokamak at General Atomics and complements the phase one biasable ring electrode. The installation consists of a 10 m long cryocondensation pump located in the divertor baffle chamber to study plasma density control by pumping of the divertor. The design is a toroidally electrically continuous liquid helium-cooled panel with 1 m2 of pumping surface. The helium panel is single point grounded to the nitrogen shield to minimize eddy currents. The nitrogen shield is toroidally continuous and grounded to the vacuum vessel in 24 locations to prevent voltage potentials from building up between the pump and vacuum vessel wall. A radiation/particle shield surrounds the nitrogen-cooled surface to minimize the heat load and prevent water molecules condensed on the nitrogen surface from being released by impact of energetic particles. Large currents (>5000 A) are driven in the helium and nitrogen panels during ohmic coil ramp up and during disruptions. The pump is designed to accommodate both the thermal and mechanical loads due to these currents. A feedthrough for the cryogens allows for both radial and vertical motion of the pump with respect to the vacuum vessel. Thermal performance measured on a prototype verified the analytical model and thermal design of the pump. Characterization tests of the installed pump show the pumping speed in deuterium is 42,000 l/sec for a pressure of 5 mTorr. Induction heating of the pump (at 300 W) resulted in no degradation of pumping speed. Plasma operations with the cryopump show a 60% lower density in H-mode.
Download or read book Kineski horoskop written by and published by . This book was released on 1987 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Design and Analysis of the Cryopump for the DIII-D Advanced Divertor by :
Download or read book Design and Analysis of the Cryopump for the DIII-D Advanced Divertor written by and published by . This book was released on 1992 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A cryocondensation pump for the DIII-D advanced diverter program is to be installed in the vacuum vessel in the fall of 1992. The purpose of the cryopump is to remove gas from the diverter, reduce recycling to the plasma, and to provide reduced density plasmas for experimental study. The pump is designed for a pumping speed of 50,000 l/s at 0.4 mtorr. The major pump components are toroidally continuous to minimize inductive voltages, thereby greatly reducing the risk of any electrical breakdown during disruptions. The cryopump consists of a 25mm Inconel tube, 10m long, cooled by liquid helium. It is surrounded by liquid nitrogen-cooled shields and a segmented ambient temperature radiation/particle shield. The outer nitrogen shield has a toroidally discontinuous copper coating to enhance thermal conductivity while maintaining a high toroidal electrical resistance to minimize electromagnetic loads during disruptions. The pump is cooled by 10 g/s of liquid helium at an inlet pressure of 115 kPa and temperature of 4.35 K. The pump is subjected to a steady-state heat load of
Book Synopsis Performance Characteristics of the DIII-D Advanced Divertor Cryopump by :
Download or read book Performance Characteristics of the DIII-D Advanced Divertor Cryopump written by and published by . This book was released on 1993 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: A cryocondensation pump, cooled by forced flow of two-phase helium, has been installed for particle exhaust from the divertor region of the DIII-D tokamak. The Inconel pumping surface is of coaxial geometry, 25.4 mm in outer diameter and 11.65 m in length. Because of the tokamak environment, the pump is designed to perform under relatively high pulsed heat loads (300 Wm−2). Results of measurements made on the pumping characteristics for D2, H2, and Ar are discussed.
Book Synopsis Design of the Advanced Divertor Pump Cryogenic System for DIII-D. by :
Download or read book Design of the Advanced Divertor Pump Cryogenic System for DIII-D. written by and published by . This book was released on 1991 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of the cryogenic system for the D3-D advanced divertor cryocondensation pump is presented. The advanced divertor incorporates a baffle chamber and bias ring located near the bottom of the D3-D vacuum vessel. A 50,000 l/s cryocondensation pump will be installed underneath the baffle for plasma particle exhaust. The pump consists of a liquid helium cooled tube operating at 4.3°K and a liquid nitrogen cooled radiation shield. Liquid helium is fed by forced flow through the cryopump. Compressed helium gas flowing through the high pressure side of a heat exchanger is regeneratively cooled by the two-phase helium leaving the pump. The cooled high pressure gaseous helium is than liquefied by a Joule-Thomson expansion valve. The liquid is returned to a storage dewar. The liquid nitrogen for the radiation shield is supplied by forced flow from a bulk storage system. Control of the cryogenic system is accomplished by a programmable logic controller.
Book Synopsis The Design and Fabrication of a Toroidally Continuous Cryocondensation Pump for the DIII-D Advanced Divertor by :
Download or read book The Design and Fabrication of a Toroidally Continuous Cryocondensation Pump for the DIII-D Advanced Divertor written by and published by . This book was released on 1991 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: A cryocondensation pump will be installed in the baffle chamber of the DIII-D tokamak in the spring of 1992. The design is complete and fabrication of this pump is in progress. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long, in the lower outer corner of the vacuum vessel interior. It consists of a 1 m2 liquid helium cooled surface surrounded by a liquid nitrogen cooled shield to limit the heat load on the helium cooled surface. The stainless steel liquid nitrogen shell has a copper coating on it to enhance thermal conductivity, but the coating is broken to keep the toroidal electrical resistance high. The liquid nitrogen cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. The whole pump is supported off the water cooled vacuum vessel wall. Key design considerations were: how to accommodate the temperature differences between the various components, developing low heat leak paths for the various supports, and maintaining electrical insulation in a low pressure environment in the presence of induced voltage spikes. A single point ground for the system was used to limit disruption induced currents and the resulting electro-mechanical forces on the pump. A testing program was used to develop coating techniques to enhance heat transfer and emissivity of the various surfaces. Fabrication tests were done to determine the best method of attaching the liquid nitrogen flow tubes to their shield surfaces. A prototype sector of the pump was built to verify fabrication and assembly techniques.
Book Synopsis Pumping Characteristics of the DIII-D Cryopump by :
Download or read book Pumping Characteristics of the DIII-D Cryopump written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning in 1992, the first of the DIII-D divertor baffles and cryocondensation pumps was installed. This open divertor configuration, located on the outermost floor of the DIII-D vessel, includes a cryopump with a predicted pumping speed of 50,000 l/s excluding obstructions such as support hardware. Taking the pump structural and support characteristics into consideration, the corrected pumping speed for D2 is 30,000 l/s [1]. In 1996, the second divertor baffle and cryopump were installed. This closed divertor structure, located on the outermost ceiling of the DIII-D vessel, has a cryopump with a predicted pumping speed of 32,000 l/s. In the fall of 1999, the third divertor baffle and cryopump will be installed. This divertor structure will be located on the 45{sup o} angled corner on the innermost ceiling of the DIII-D vessel, known as the private flux region of the plasma configuration. With hardware supports factored into the pumping speed calculation, the private flux cryopump is expected to have a pumping speed of 15,000 l/s. There was question regarding the effectiveness of the private flux cryopump due to the close proximity of the private flux baffle. This led to a conductance calculation study of the impact of rotating the cryopump aperture by 180{sup o} to allow for greater particle and gas exhaust into the cryopump's helium panel. This study concluded that the cost and schedule impact of changing the private flux cryopump orientation and design did not warrant the possible 20% (3,000 l/s) increase in pumping ability gained by rotating the cryopump aperture 180{sup o}. The comparison of pumping speed of the first two cryocondensation pumps with the measured results will be presented as well as the calculation of the pumping speed for the private flux cryopump now being installed.
Book Synopsis The Development of an In-vessel Cryopump System for the DIII-D Tokamak by :
Download or read book The Development of an In-vessel Cryopump System for the DIII-D Tokamak written by and published by . This book was released on 1993 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design, testing and initial operation of the DIII-D advanced divertor cryocondensation pumping system is presented. The pump resides inside the tokamak plasma containment vessel where it provides particle exhaust pumping, and it is subjected to Joule heating and hot particle heat loads during each 10 second discharge. In addition, the pump must withstand plasma disruption induced electromagnetic forces and 400°C bake-out temperatures. Cooling is accomplished by forced flow liquid helium with the two-phase helium exhaust passing through a reliquefier for thermal efficiency. A prototype pump was constructed to study surface temperature rise as a function of flow geometry, applied heat load, helium mass flow rate, and pump outlet conditions. Prototype testing led to the development of a special geometry which was demonstrated to enhance two-phase flow stability and overall heat transfer. During initial operation, deuterium pumping speeds of 32,000 L/s at 2 mTorr pressure were achieved with a helium flow rate of 5 g/s. This speed was maintained during 300 W, 8 s long test beat pulses which meets operational goals.
Book Synopsis Advances in Cryogenic Engineering by : Peter Kittel
Download or read book Advances in Cryogenic Engineering written by Peter Kittel and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 2020 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Albuquerque Convention Center was the venue for the 1993 Cryogenic Engineering Conference. The meeting was held jointly with the International Cryogenic Materials Conference. Walter F. Stewart, of Los Alamos National Laboratory, was conference chairman. Albuquerque is near Los Alamos National Laboratory which has been a significant contributor to the cryogenics community since the early days of the Manhattan Project. Albuquerque is also the home of the Air Force's Phillips Laboratory which has a lead role in developing cryocoolers. The program consisted of 322 CEC papers, more than a 30% increase from CEC-91 and 20% more than CEC-89. This was the largest number of papers ever submitted to the CEC. Of these, 249 papers are published here, in Volume 39 of Advances in Cryogenic Engineering. Once again the volume is published in two books. This volume includes a cumulative index for the CEC volumes from 1975-1993 (volumes 21,23,25,27,29,31,33,35,37, and 39 of Advances in Cryogenic Engineering). The first 20 volumes are indexed in Volume 20. A companion cumulative index for the ICMC volumes (volumes 22 through 40) appears in Volume 40. This is my first volume as editor. I would not have been able to have done it without the assistance of the many reviewers. Especially appreciated was the instruction manual left me by the previous editor, Ron Fast.
Book Synopsis Design and Analysis of the Cryopump for the DIII-D Upper Divertor by :
Download or read book Design and Analysis of the Cryopump for the DIII-D Upper Divertor written by and published by . This book was released on 1999 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: A cryocondensation pump for the upper inboard divertor on DIII-D is to be installed in the vacuum vessel in the fall of 1999. The cryopump removes neutral gas particles from the divertor and prevents recycling to the plasma. This pump is designed for a pumping speed of 18,000 l/s at 0.4 mTorr. The cryopump is toroidally continuous to minimize inductive voltages and avoid electrical breakdown during disruptions. The cryopump consists of a 25 mm Inconel tube cooled by liquid helium and is surrounded by nitrogen cooled shields. A segmented ambient temperature radiation/particle shield protects the nitrogen shields. The pump is subjected to a steady state heat load of less than 10 W due to conduction and radiation heat transfer. The helium tube will be subjected to Joule heating of less than 300 J due to induced current and a particle load of less than 12 W during plasma operation. The thermal design of the cryopump requires that it be cooled by 5 g/s liquid helium at an inlet pressure of 115 kPa and a temperature of 4.35 K. Thermal analysis and tests show that the helium tube can absorb a transient heat load of up to 100 W for 10 s and still pump deuterium at 6.3 K. Disruptions induce toroidal currents in the helium line and nitrogen shields. These currents cross the rapidly changing magnetic fields, applying complex dynamic loads on the cryopump. The forces on the pump are extrapolated from magnetic measurements from DIII-D plasma disruptions and scaled to a 3 MA disruption. The supports for the nitrogen shield consist of a racetrack design, which are stiff for reacting the disruption loads, but are radially flexible to allow differential thermal displacements with the vacuum vessel. Static and dynamic finite element analyses of the cryopump show that the stresses and displacements over a range of disruption and thermal loadings are acceptable.
Book Synopsis Fusion Technology 1994 by : K. Herschbach
Download or read book Fusion Technology 1994 written by K. Herschbach and published by Newnes. This book was released on 2012-12-02 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the Symposium on Fusion Technology (SOFT) conference is to set the stage for the exchange of information on the design, construction, and operation of fusion experiments and the technology which is being developed for the next-step devices and for fusion reactors. These proceedings therefore present an up-to-date and throrough review of the state-of-the art in this dynamic field.
Book Synopsis Fusion Technology 1992 by : C. Ferro
Download or read book Fusion Technology 1992 written by C. Ferro and published by Elsevier. This book was released on 2013-10-22 with total page 1894 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of the biennial series of symposia on Fusion Technology organized by the European Fusion Laboratories, is the exchange of information on the design, construction and operation of fusion experiments and on the technology being developed for the next-step devices and fusion reactors. The coverage of the volume includes the technological aspects of fusion reactors in relation to new developments, thus forming a guideline for the definition of future work. These proceedings comprise three volumes and contain both the invited lectures and contributed papers presented at the symposium, which was attended by 569 participants from around the globe. The 343 papers, including 12 invited papers, characterise the increasing interest of industry in the fusion programme, giving a broad and current overview on the progress and trends fusion technology is experiencing now, as well as indicating the future for fusion devices.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Verification Test for Helium Panel of Cryopump for DIII-D Advanced Divertor by :
Download or read book Verification Test for Helium Panel of Cryopump for DIII-D Advanced Divertor written by and published by . This book was released on 1991 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is planned to install a cryogenic pump in the lower divertor portion of the D3-D tokamak with a pumping speed of 50000l/s and an exhaust of 2670 Pa-l/s (20 Torr-ls). A coaxial counter flow configuration has been chosen for the helium panel of this cryogenic pump. This paper evaluates cooldown rates and fluid stability of this configuration. A prototypic test was performed at General Atomics (GA) to increase confidence in the design. It was concluded that the helium panel cooldown rate agreed quite well with analytical prediction and was within acceptable limits. The design flow rate proved stable and two-phase pressure drop can be predicted quite accurately. 8 refs., 5 figs., 1 tab.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Advances in Cryogenic Engineering by : Klaus D. Timmerhaus
Download or read book Advances in Cryogenic Engineering written by Klaus D. Timmerhaus and published by Springer. This book was released on 1994-06-30 with total page 1096 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the 1993 conference held in Albuquerque, NM, USA , July 12-16, 1993.
